Sidearm effects. Synthesis, structural characterization, and reactivity of lanthanides incorporating a linked carboranyl-indenyl ligand with a tethered amine group

Article abstract of DOI:10.1021/om049778+

A new amine-functionalized carboranyl-indenyl hybrid ligand shows unique properties in stabilizing various kinds of lanthanocene chloride complexes via increasing steric effects imposed by the coordination of NMe₂ to the central metal ion, leading to the isolation of kinetic products and monomeric neutral species. Treatment of Me₂SiCl(C₉H ₆CH₂CH₂NMe₂) with 1 equiv of Li ₂C₂B₁₀H₁₀ afforded the monolithium salt [Me₂Si(C₉H₅CH₂CH ₂NMe₂)-(C₂B₁₀H₁₁)] Li(OEt₂) (2). Interaction of 2 with 1 equiv of n-BuLi produced the dilithium salt [Me₂Si(C₉H₅CH₂CH ₂NMe₂)(C₂B₁₀H₁₀)]Li ₂(OEt₂)₂ (3). Treatment of 3 with 1 equiv of YbCl₃ gave [{η⁶:η¹:σ-Me ₂Si(C₉H₅CH₂CH₂NMe ₂)(C₂B₁₀H₁₀)}YbCl ₂][Li(THF)₄] (4). Upon heating, 4 was converted to [{η⁵:η¹:σ-Me₂Si(C ₉H₅CH₂CH₂NMe₂)(C ₂B₁₀H₁₀)}Yb(μ-Cl)_1.5] ₂[Li(THF)₄] (6) and finally to [{η¹: η¹:σ-Me₂Si(C₉H₅CH ₂CH₂NMe₂)(C₂B₁₀H ₁₀)}Yb(μ-Cl)]₂ (7) via the elimination of LiCl. Treatment of 6 or its Sm analogue 5 with 2 equiv of sodium amide gave [η⁵:η¹:σ-Me₂-Si(C ₉H₅CH₂CH₂NMe₂)(C ₂B₁₀H₁₀)]Yb(NHC₆H ₃-2,6-Pr₂ⁱ) (9) or [η⁵: η¹:σMe₂Si(C₉H₅CH ₂CH₂-NMe₂)(C₂B₁₀H ₁₀)]Sm(μ-NHC₆H₃-2,6-Pr₂ ⁱ)(μ-Cl)Li(THF) (8). An equimolar reaction of SmI₂ with 3 generated, after addition of LiCl, [{η⁵:η¹: σ⁶-Me₂Si(C₉H₅CH ₂CH₂NMe₂)(C₂B₁₀H ₁₀)Sm}₂-(μ-Cl)] [Li(THF)₄] (10). In sharp contrast, a less reactive YbI₂ reacted with 3 in THF, producing only the salt metathesis product [η⁵:σ¹:σ- Me₂Si(C₉H₅CH₂CH₂NMe ₂)(C₂B₁₀H₁₀)]Yb(DME) (11). 11 reacted with 1 equiv of 3 to give the ionic complex {[(μ-η⁵: η²):η¹:σ-Me₂Si(C ₉H₅CH₂CH₂-NMe₂)(C ₂B₁₀H₁₀)]₂Yb}{Li(THF) ₂}₂ (12). All complexes were characterized by spectroscopic techniques and elemental analyses. Their structures were all further confirmed by single-crystal X-ray analyses.

Full text of DOI:10.1021/om049778+

3780
Organometallics 2004, 23, 3780-3787
Sid ea r m Effects. Syn th esis, Str u ctu r a l Ch a r a cter iza tion ,
a n d Rea ctivity of La n th a n id es In cor p or a tin g a Lin k ed
Ca r bor a n yl-In d en yl Liga n d w ith a Teth er ed Am in e
Gr ou p
Shaowu Wang,†,‡ Hung-Wing Li,† and Zuowei Xie*,†
Department of Chemistry, The Chinese University of Hong Kong, Shatin,
New Territories, Hong Kong, China, and Institute of Organic Chemistry, School of Chemistry
and Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China
Received March 30, 2004
A new amine-functionalized carboranyl-indenyl hybrid ligand shows unique properties in
stabilizing various kinds of lanthanocene chloride complexes via increasing steric effects
imposed by the coordination of NMe2 to the central metal ion, leading to the isolation of
kinetic products and monomeric neutral species. Treatment of Me2SiCl(C9H6CH2CH2NMe2)
with 1 equiv of Li2C2B10H10 afforded the monolithium salt [Me2Si(C9H5CH2CH2NMe2)-
(C2B10H11)]Li(OEt2) (2). Interaction of 2 with 1 equiv of n-BuLi produced the dilithium salt
[Me2Si(C9H5CH2CH2NMe2)(C2B10H10)]Li2(OEt2)2 (3). Treatment of 3 with 1 equiv of YbCl3
gave [{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)}YbCl2][Li(THF)4] (4). Upon heating, 4 was
converted to [{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)}Yb(µ-Cl)1.5]2[Li(THF)4] (6) and
finally to [{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)}Yb(µ-Cl)]2 (7) via the elimination of
LiCl. Treatment of 6 or its Sm analogue 5 with 2 equiv of sodium amide gave [η5:η1:σ-Me2-
Si(C9H5CH2CH2NMe2)(C2B10H10)]Yb(NHC6H3-2,6-Pri ) (9) or [η5:η1:σ-Me2Si(C9H5CH2CH2-
2
NMe2)(C2B10H10)]Sm(µ-NHC6H3-2,6-Pri )(µ-Cl)Li(THF) (8). An equimolar reaction of SmI2
2
with 3 generated, after addition of LiCl, [{η5:η1:η6-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)Sm}2-
(µ-Cl)][Li(THF)4] (10). In sharp contrast, a less reactive YbI2 reacted with 3 in THF, producing
only the salt metathesis product [η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)]Yb(DME) (11).
11 reacted with 1 equiv of 3 to give the ionic complex {[(µ-η5:η2):η1:σ-Me2Si(C9H5CH2CH2-
NMe2)(C2B10H10)]2Yb}{Li(THF)2}2 (12). All complexes were characterized by spectroscopic
techniques and elemental analyses. Their structures were all further confirmed by single-
crystal X-ray analyses.
In tr od u ction
contribution, we report a full account on the synthesis,
structural characterization, and reactivity of lanthan-
ides derived from this new ligand.4 Similarities and
differences between [Me2Si(C9H5CH2CH2NMe2)(C2B10-
H10)]2-and [Me2Si(C9H5CH2CH2OMe)(C2B10H10)]2- in
coordination chemistry are also discussed.
Cyclopentadienyl or indenyl ligands with Lewis base
functionalities have found many applications in rare
earth chemistry.1,2 Our very recent work shows that the
ether substituent on the five-membered ring of the
indenyl unit in linked carboranyl-indenyl hybrid ligands
has significant effects on the stability and reactivity of
the resulting organo-rare-earth complexes via tempo-
rarily and reversibly coordinating to the metal ion.3
Considering very high oxophilicity of lanthanides and
the steric demands of OMe versus NMe2, we have
extended our research to amine-functionalized carbo-
ranyl-indenyl hybrid ligands. The results indicate that
[Me2Si(C9H5CH2CH2NMe2)(C2B10H10)]2- exhibits some
interesting features in coordination chemistry. In this
Exp er im en ta l Section
Gen er a l P r oced u r es. All experiments were performed
under an atmosphere of dry dinitrogen with the rigid exclusion
of air and moisture using standard Schlenk or cannula
techniques, or in a glovebox. All organic solvents were freshly
distilled from sodium benzophenone ketyl immediately prior
to use. LnI2(THF)x (Ln ) Sm, Yb),5 C9H7CH2CH2NMe2,6 2,6-
8
Pri -C6H3NHNa,7 and Li2C2B10H10 were prepared according
2
to literature methods. All other chemicals were purchased from
Aldrich Chemical Co. and used as received unless otherwise
noted. Infrared spectra were obtained from KBr pellets
prepared in the glovebox on a Perkin-Elmer 1600 Fourier
* Corresponding author. Fax: (852)26035057. Tel: (852)26096344.
E-mail: zxie@cuhk.edu.hk.
† The Chinese University of Hong Kong.
‡ Anhui Normal University.
(1) For recent reviews, see: (a) Arndt, S.; Okuda, J . Chem. Rev.
2002, 102, 1953. (b) Okuda, J . J . Chem. Soc., Dalton Trans. 2003, 2367.
(2) For reviews, see: (a) Schumann, H.; Messe-Markscheffel, J . A.;
Esser, L. Chem. Rev. 1995, 95, 865. (b) Edelmann, F. T. In Compre-
hensive Organometallic Chemistry II; Abel, E. W., Stone, F. A. G.,
Wilkinson, G., Eds.; Pergamon: New York, 1995; Vol. 4, p 11.
(3) Wang, S.; Li, H.-W.; Xie, Z. Organometallics 2004, 23, 2469.
(4) For preliminary communication, see: Wang, S.; Li, H.-W.; Xie,
Z. Organometallics 2001, 20, 3624.
(5) Girard, P.; Namy, J . L.; Kagan, H. B. J . Am. Chem. Soc. 1980,
102, 2693.
(6) Qian, C.; Li, H.; Sun, J .; Nie, W. J . Organomet. Chem. 1999,
585, 59.
(7) Chan, H.-S.; Li, H.-W.; Xie, Z. Chem. Commun. 2002, 652.
10.1021/om049778+ CCC: $27.50 © 2004 American Chemical Society
Publication on Web 06/23/2004

Linked Carboranyl-Indenyl Ligand
Organometallics, Vol. 23, No. 16, 2004 3781
transform spectrometer. 1H and 13C NMR spectra were re-
corded on a Bruker DPX 300 spectrometer at 300.13 and 75.47
MHz, respectively. 11B NMR spectra were recorded on a Varian
Inova 400 spectrometer at 128.32 MHz. All chemical shifts are
reported in δ units with reference to the residual protons of
the deuterated solvents for proton and carbon chemical shifts
and to external BF3‚OEt2 (0.00 ppm) for boron chemical shifts.
Elemental analyses were performed by MEDAC Ltd., U.K.
P r ep a r a tion of Me2Si(C9H6CH2CH2NMe2)Cl (1). To an
Et2O (200 mL) solution of Me2NCH2CH2C9H7 (5.10 g, 0.027
mol) was slowly added a 1.60 M solution of n-BuLi in n-hexane
(17.0 mL, 0.027 mol) at 0 °C, and the mixture was warmed to
room temperature and stirred overnight. The resulting solution
was then cooled to 0 °C, and Me2SiCl2 (14.0 mL, 0.108 mol)
was quickly added in one portion. The mixture was stirred at
room temperature overnight. The precipitate was filtered off.
Removal of the solvent and excess Me2SiCl2 gave 1 as a pale
yellow oil (6.60 g, 87%), which was pure enough for the next
reaction step. 1H NMR (CDCl3): δ 7.55 (d, J ) 7.5 Hz, 1H),
7.48 (d, J ) 7.5 Hz, 1H), 7.32 (dd, J ) 7.5 and 7.5 Hz, 1H),
7.23 (dd, J ) 7.5 and 7.5 Hz, 1H), 6.36 (s, 1H), 3.64 (s, 1H)
(C9H6), 2.92 (m, 2H), 2.78 (m, 2H), 2.49 (s, 6H) (CH2CH2N-
(CH3)2), 0.22 (s, 3H), 0.17 (s, 3H) (Si(CH3)2). 13C NMR
(CDCl3): δ 144.80, 143.99, 141.52, 129.22, 126.29, 125.18,
124.06, 119.84, 45.48 (C9H6), 58.88, 46.40, 26.12 (CH2CH2N-
(CH3)2), 0.52, 0.43 (Si(CH3)2). MS (EI): 279 (M+).
P r ep a r a tion of [{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2-
10H10)}YbCl2][Li(THF )4] (4). To a suspension of YbCl3 (0.28
B
g, 1.0 mmol) in THF (20 mL) was slowly added a THF (10 mL)
solution of 3 (0.55 g, 1.0 mmol) at room temperature. The
reaction mixture was stirred at room temperature for 10 h.
The color of the solution gradually changed from colorless to
purple with disappearance of YbCl3. The solvent was removed
under vacuum, affording a sticky purple solid, to which was
added 15 mL of toluene. After removal of the precipitate, the
clear solution was concentrated to about 10 mL. 4 was isolated
as purple crystals after this solution stood at room temperature
for 4 days (0.72 g, 78%). 1H NMR (pyridine-d5): δ 3.52 (s), 1.43
(s) (THF), plus 22.9 (br s), 13.6 (br s), 7.91 (s), 7.78 (s), 3.42
(s), 2.80 (s), 2.14 (s), 0.65 (s), -6.8 (br s), -13.6 (br s). 11B NMR
(pyridine-d5): δ -2.98 (1), -7.51 (1), -10.76 (3), -20.19 (2),
-29.06 (2), -61.32 (1). IR (KBr, cm-1): νBH 2563 (vs). Anal.
Calcd for C29H55B10Cl2LiNO3SiYb (4 - THF): C, 40.84; H, 6.50;
N, 1.64. Found: C, 41.11; H, 6.58; N, 1.51.
P r epar ation of [{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10
-
H
10)}Sm (µ-Cl)1.5]2[Li(THF )4]‚THF (5‚THF ). To a suspension
of SmCl3 (0.26 g, 1.0 mmol) in THF (15 mL) was slowly added
a THF solution of 3 (0.55 g, 1.0 mmol) at room temperature,
and the mixture was stirred overnight. The color of the solution
changed gradually from colorless to orange with disappearance
of SmCl3. After removal of the solvent, toluene (15 mL) was
added to the sticky solid. The mixture was then stirred for 1
h, and the precipitate was filtered off. The clear solution was
concentrated to about 10 mL. 5‚THF was isolated as orange-
red crystals after this solution stood at room temperature for
4 days (0.49 g, 63%). 1H NMR (pyridine-d5): δ 3.66 (s), 1.64
(s) (THF), plus many broad, unresolved resonances. 11B NMR
(pyridine-d5): δ -0.66 (2), -4.29 (4), -7.43 (4). IR (KBr, cm-1):
νBH 2554 (vs). Anal. Calcd for C50H94B20Cl3LiN2O4Si2Sm2 (5):
C, 40.75; H, 6.43; N, 1.90. Found: C, 40.59; H, 6.31; N, 1.79.
P r ep a r a tion of [Me2Si(C9H5CH2CH2NMe2)(C2B10H11)]-
Li(OEt2) (2). To a solution of o-C2B10H12 (3.25 g, 22.6 mmol)
in a dry toluene/diethyl ether (2:1, 20 mL) mixture was slowly
added a 1.6 M solution of n-BuLi in hexane (28.5 mL, 45.6
mmol) at 0 °C, and the mixture was warmed to room temper-
ature and stirred for 1 h. The resulting solution was then
cooled to 0 °C, and a solution of 1 (6.33 g, 22.6 mmol) in a
toluene/diethyl ether (2:1, 20 mL) mixture was slowly added.
The mixture was stirred at room temperature for 25 h. After
removal of the solvents, the resulting sticky solid was extracted
with diethyl ether (20 mL × 2). The ether solutions were
combined and concentrated to give a pale yellow solid. This
solid was washed with n-hexane (10 mL × 2) and dried in a
vacuum, affording 2 as a pale yellow solid (8.40 g, 79%). 1H
NMR (pyridine-d5): δ 8.07 (d, J ) 7.8 Hz, 1H), 7.92 (d, J )
7.2 Hz, 1H), 7.26 (s, 1H), 7.11 (m, 2H) (C9H5), 3.74 (br s, 1H)
(cage CH), 3.48 (m, 2H), 2.93 (m, 2H), 3.28 (s, 6H) (CH2CH2N-
(CH3)2), 3.36 (q, J ) 7.2 Hz, 4H), 1.12 (t, J ) 7.2 Hz, 6H)
(O(CH2CH3)2), 0.81 (s, 6H) (Si(CH3)2). 13C NMR (pyridine-d5):
δ 139.00, 133.23, 123.92, 121.10, 119.05, 116.23, 115.18,
110.82, 88.16 (C9H5), 63.22, 45.22, 26.33 (CH2CH2N(CH3)2),
79.11, 66.35 (C2B10H11), 66.16, 15.61 (O(CH2CH3)2), 1.55 (Si-
(CH3)2). 11B NMR (pyridine-d5): δ -5.05 (2), -10.45 (3), -14.49
P r epar ation of [{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10
-
H
10)}Yb(µ-Cl)1.5]2[Li(THF )4]‚C7H8 (6‚C7H8). A suspension of
4 (0.30 g, 0.32 mmol) in a mixed solvent of toluene/THF (7:1,
15 mL) was refluxed for 2 h. The white precipitate was filtered
off. The clear solution was then concentrated to about 8 mL.
6‚C7H8 was isolated as blue crystals after this solution stood
at room temperature for 2 days (0.16 g, 62%). 1H NMR
(pyridine-d5): δ 3.55 (s), 1.52 (s) (THF), plus many broad,
unresolved resonances. 11B NMR (pyridine-d5): δ -1.39 (2),
-6.43 (2), -12.82 (6). IR (KBr, cm-1): νBH 2570 (vs). Anal.
Calcd for C46H86B20Cl3LiN2O3Si2Yb2 (6 - THF): C, 38.18; H,
5.99; N, 1.94. Found: C, 38.27; H, 6.10; N, 1.80.
P r epar ation of [{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10
-
H
10)}Yb(µ-Cl)]2 (7). A suspension of 6‚C7H8 (0.26 g, 0.16
(5). IR (KBr, cm-1): νBH 2565 (vs). Anal. Calcd for C17H32B10
-
mmol) in a mixed solvent of toluene/THF (10:1, 15 mL) was
refluxed for 6 h until all LiCl precipitated out. After removal
of the white precipitate, the clear solution was then concen-
trated to about 10 mL. 7 was isolated as blue crystals after
this solution stood at room temperature for 3 days (0.11 g,
LiNSi (2 - Et2O): C, 51.88; H, 8.20; N, 3.56. Found: C, 52.05;
H, 8.39; N, 3.38.
P r ep a r a tion of [Me2Si(C9H5CH2CH2NMe2)(C2B10H10)]-
Li2(OEt2)2 (3). To a suspension of 2 (7.50 g, 16.0 mmol) in a
mixed solvent of n-hexane and diethyl ether (2:1, 65 mL) was
slowly added a 1.60 M solution of n-BuLi in hexane (10.5 mL,
16.8 mmol) at 0 °C, and the mixture was stirred at room
temperature overnight. Removal of the solvent gave a yellow
solid, which was washed with n-hexane (3 × 15 mL), affording
3 as a pale yellow powder (7.90 g, 90%). 1H NMR (pyridine-
d5): δ 8.16 (d, J ) 8.7 Hz, 1H), 7.83 (d, J ) 8.7 Hz, 1H), 7.34
(s, 1H), 7.06 (m, 2H) (C9H5), 3.18 (m, 2H), 2.54 (m, 2H), 2.16
(s, 6H) (CH2CH2N(CH3)2), 3.39 (m, 8H), 1.13 (m, 12H)
(O(CH2CH3)2), 0.83 (s, 6H) (Si(CH3)2). 13C NMR (pyridine-d5):
δ 138.09, 132.79, 125.72, 122.20, 118.14, 115.43, 114.21,
110.89, 89.18 (C9H5), 62.62, 46.05, 27.25 (CH2CH2N(CH3)2),
78.18 (C2B10H11), 66.17, 15.90 (O(CH2CH3)2), 2.21 (Si(CH3)2).
11B NMR (pyridine-d5): δ 6.97 (1), 6.52 (1), 6.01 (1), 2.38 (2),
-0.14 (4), -1.96 (1). IR (KBr, cm-1): νBH 2556 (vs). Anal. Calcd
for C21H41B10Li2NOSi (3 - Et2O): C, 53.25; H, 8.73; N, 2.96.
Found: C, 53.09; H, 8.69; N, 2.89.
1
58%). H NMR (pyridine-d5): δ 23.0 (s), 7.96 (d, J ) 7.2 Hz),
7.83 (d, J ) 7.2 Hz), 3.37 (br s), 2.82 (br s), 2.20 (s), 0.70 (s),
-6.7 (br s), -13.6 (br s). 11B NMR (pyridine-d5): δ -3.51 (3),
-8.72 (2), -14.44 (5). IR (KBr, cm-1): νBH 2553 (vs). Anal.
Calcd for C34H62B20Cl2N2Si2Yb2: C, 34.37; H, 5.26; N, 2.36.
Found: C, 34.18; H, 5.19; N, 2.18.
P r ep a r a t ion of [η5:η1:σ-Me2Si(C9H 5CH 2CH 2NMe2)(C2-
B
10H10)]Sm (µ-NHC6H3-2,6-P r i2)(µ-Cl)Li(THF ) (8). To a THF
(15 mL) solution of 5‚THF (0.26 g, 0.17 mmol) was slowly
added a THF (10 mL) solution of NaNHC6H3-2,6-Pri (0.067
2
g, 0.34 mmol) at room temperature, and the mixture was
stirred overnight. After removal of the solvent, toluene (15 mL)
was added to the resulting orange solid. The mixture was then
refluxed for 1 h. The white precipitate was filtered off, and
the clear orange solution was concentrated to about 8 mL. 8
was isolated as orange crystals after this solution stood at room
1
temperature for 4 days (0.19 g, 68%). H NMR (pyridine-d5):

3782 Organometallics, Vol. 23, No. 16, 2004
Wang et al.
many broad, unresolved resonances. 11B NMR (pyridine-d5):
δ -4.12 (1), -12.99 (9). IR (KBr, cm-1): νBH 2546 (vs). Anal.
Calcd for C29H49B10ClLiN2SiSm (8 - THF): C, 46.15; H, 6.54;
N, 3.71. Found: C, 46.06; H, 6.61; N, 3.82.
oily residue was washed with hot toluene (2 × 10 mL). The
resulting solid was then extracted with a mixed solvent of
toluene and THF (10:1, 3 × 7 mL). The solutions were
combined and concentrated to about 15 mL. 12 was obtained
as red crystals after this solution stood at room temperature
for 5 days (0.37 g, 71%). 1H NMR (pyridine-d5): δ 8.24 (m,
2H), 8.14 (m, 1H), 7.82 (m, 1H), 7.34 (s, 1H), 7.05 (m, 4H),
6.93 (s, 1H) (C9H5), 3.18 (m, 4H), 2.54 (m, 4H), 2.37 (s, 12H)
(CH2CH2N(CH3)2), 3.65 (m, 16H), 1.62 (m, 16H) (C4H8O), 0.92
P r epar ation of [η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10
-
H
10)]Yb(NHC6H3-2,6-P r i2)‚0.5C6H6 (9‚0.5C6H6). This complex
was prepared as purple crystals from 4 (0.30 g, 0.32 mmol)
and NaNHC6H3-2,6-Pri (0.067 g, 0.34 mmol) in THF (25 mL)
2
at room temperature using the procedure identical to that
reported for 8 except for using benzene instead of toluene:
yield 0.19 g (77%). 1H NMR (pyridine-d5): many broad,
unresolved resonances. 11B NMR (pyridine-d5): δ 0.03 (1),
-6.43 (1), -10.57 (2), -31.90 (6). IR (KBr, cm-1): νBH 2562
(vs). Anal. Calcd for C29H49B10N2SiYb (9): C, 47.39; H, 6.72;
N, 3.81. Found: C, 47.15; H, 6.91; N, 3.66.
(s, 6H), 0.79 (s, 6H) (Si(CH3)2). 13C NMR (pyridine-d5):
δ
139.21, 137.83, 135.73, 130.13, 127.14, 123.29, 120.25, 116.52,
112.48 (C9H5), 63.72, 47.32, 28.35 (CH2CH2N(CH3)2), 81.99,
64.32 (C2B10H11), 69.31, 27.28 (THF), 2.02, 1.39 (Si(CH3)2). 11
B
NMR (pyridine-d5): δ -0.30 (2), -3.49 (6), -7.98 (12). IR (KBr,
cm-1): νBH 2564 (vs). Anal. Calcd for C42H78B20Li2N2O2Si2Yb
(12 - 2THF): C, 45.76; H, 7.13; N, 2.54. Found: C, 45.35; H,
7.37; N, 2.25.
This complex was directly prepared in 67% yield from the
reaction of YbI2(THF)x with 2 equiv of 3.
This complex was also prepared from the reaction of 6 or 7
with NaNHC6H3-2,6-Pri in 65% or 70% yield, respectively.
2
P r ep a r a tion of [({η5:η1:η6-Me2Si(C9H5CH2CH2NMe2)(C2-
10H10)}Sm )2(µ-Cl)][Li(THF )4]‚C7H8 (10‚C7H8). To a THF
B
X-r a y Str u ctu r e Deter m in a tion . All single crystals were
immersed in Paraton-N oil and sealed under N2 in thin-walled
glass capillaries. Data were collected at 293 K on a Bruker
SMART 1000 CCD diffractometer using Mo KR radiation. An
empirical absorption correction was applied using the SADABS
program.9 All structures were solved by direct methods and
subsequent Fourier difference techniques and refined aniso-
tropically for all non-hydrogen atoms by full-matrix least-
squares calculations on F2 using the SHELXTL program
package.10 Most of the carborane hydrogen atoms were located
from difference Fourier syntheses. All other hydrogen atoms
were geometrically fixed using the riding model. Crystal data
and details of data collection and structure refinements are
given in Tables 1 and 2, respectively. Selected bond lengths
and angles are compiled in Table 3. Further details are
included in the Supporting Information.
Resu lts a n d Discu ssion
Liga n d . Reaction of Li[C9H6CH2CH2NMe2] with ex-
cess Me2SiCl2 in Et2O gave Me2SiCl(C9H6CH2CH2NMe2)
(1) in 87% yield. Treatment of 1 with 1 equiv of
Li2C2B10H10 in toluene/Et2O afforded the monolithium
salt [Me2Si(C9H5CH2CH2NMe2)(C2B10H11)]Li(OEt2) (2)
in 79% yield. Interaction of 2 with 1 equiv of n-BuLi in
Et2O/hexane produced the dilithium salt [Me2Si(C9H5-
CH2CH2NMe2)(C2B10H10)]Li2(OEt2)2 (3) in 90% yield. 3
is slightly soluble in ether, whereas 2 is highly soluble.
Therefore, they were easily separated. These transfor-
mations are outlined in Scheme 1.
The 1H NMR spectra of both 2 and 3 exhibit the same
splitting pattern with different chemical shifts and
support one Et2O molecule per carboranyl in 2 and two
Et2O molecules per carboranyl in 3, respectively. In
1
addition, the H NMR spectrum of 2 displays a broad
singlet at δ ) 3.74 ppm attributable to the cage CH
proton, supporting that 2 is a monolithium salt. The 13
C
NMR data are in line with the results from the corre-
1
sponding H NMR spectra. The 11B NMR spectra show
a 2:3:5 splitting pattern for 2 and a 1:1:1:2:4:1 splitting
pattern for 3, respectively, which are different from
those observed in the corresponding ether-functionalized
ligands.3
P r epar ation of {[(µ-η5:η2):η1:σ-Me2Si(C9H5CH2CH2NMe2)-
(C2B10H10)]2Yb}{Li(THF )2}2 (12). To a THF (10 mL) solution
of 11 (0.27 g, 0.42 mmol) was slowly added a THF (15 mL)
solution of 3 (0.23 g, 0.42 mmol) at room temperature, and
the mixture was stirred overnight. The color of the solution
changed from orange to red. After removal of the solvent, the
(8) Xie, Z. Acc. Chem. Res. 2003, 36, 1.
(9) Sheldrick, G. M. SADABS: Program for Empirical Absorption
Correction of Area Detector Data; University of Go¨ttingen: Germany,
1996.
(10) SHELXTL V 5.03 Program Package; Siemens Analytical X-ray
Instruments, Inc.: Madison, WI, 1995.

Linked Carboranyl-Indenyl Ligand
Organometallics, Vol. 23, No. 16, 2004 3783
Ta ble 1. Cr ysta l Da ta a n d Su m m a r y of Da ta Collection a n d Refin em en t for 4-8
4
5‚THF
6‚toluene
7
8
formula
C
33H63B10Cl2LiNO4SiYb C54H102B20Cl3LiN2O5Si2Sm2
C
57H102B20Cl3LiN2O4Si2Yb2
C
34H62B20Cl2N2Si2Y2
C
33H57B10ClLiN2OSiSm
cryst size (mm) 0.70 × 0.40 × 0.30
0.50 × 0.50 × 0.08
1545.8
0.40 × 0.38 × 0.25
0.38 × 0.20 × 0.18
0.30 × 0.21 × 0.11
fw
924.9
1611.2
1188.2
826.7
cryst syst
space group
a, Å
b, Å
c, Å
triclinic
P1h
monoclinic
P21/n
20.187(1)
17.912(1)
22.299(1)
90
108.92(1)
90
7628.0(5)
4
monoclinic
P21/n
20.041(4)
17.837(4)
22.468(5)
90
109.54(3)
90
7569(3)
4
triclinic
P1h
triclinic
P1h
10.482(1)
11.254(1)
21.216(1)
91.24(1)
99.03(1)
92.60(1)
2468.0(3)
2
10.201(2)
10.767(2)
12.723(3)
82.27(3)
71.48(3)
68.25(3)
1230.5(4)
1
9.897(3)
11.163(3)
23.517(7)
85.20(1)
79.46(1)
68.98(1)
2384(1)
2
R, deg
â, deg
γ, deg
V, Å3
Z
D
calcd, Mg/m3
1.245
1.346
1.414
1.603
1.152
radiation (λ), Å Mo KR (0.71073)
Mo KR (0.71073)
3.2 to 50.0
1.703
Mo KR (0.71073)
3.2 to 50.0
2.636
Mo KR (0.71073)
4.0.0 to 50.0
3.964
Mo KR (0.71073)
3.6 to 50.0
1.338
2θ range, deg 3.6 to 50.0
µ, mm-1
F(000)
2.059
942
3144
1312
582
846
no. of obsd
reflns
6365
11942
8011
3494
6113
no. of params 462
refnd
785
737
281
443
goodness of fit 1.125
0.986
0.045
0.107
1.060
0.101
0.244
1.009
0.060
0.164
1.065
0.097
0.250
R1
0.051
0.137
wR2
Ta ble 2. Cr ysta l Da ta a n d Su m m a r y of Da ta Collection a n d Refin em en t for 9-12
9‚0.5(benzene)
10‚toluene
11
12
formula
C
32H52B10N2SiYb
C57H102B20ClLiN2 O4Si2Sm2
C
21H41B10NO2SiYb
C50H94B20Li2N2 O4Si2Yb
cryst size (mm)
fw
cryst syst
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
0.35 × 0.30 × 0.17
0.50 × 0.30 × 0.21
0.35 × 0.15 × 0.08
0.25 × 0.20 × 0.18
1246.6
orthorhombic
Pbcn
14.893(3)
19.577(4)
23.115(5)
90
90
90
6739(2)
4
1.229
774.0
1494.9
648.8
monoclinic
P21/n
10.726(4)
16.012(5)
22.289(7)
90
95.86(1)
90
3808(2)
4
triclinic
P1h
monoclinic
P21/n
12.234(1)
15.867(2)
15.090(2)
90
90.12(1)
90
2929.2(5)
4
10.662(2)
15.748(3)
24.832(5)
104.00(3)
99.43(3)
103.29(3)
3829.1(13)
2
Z
D
calcd, Mg/m3
1.350
1.297
1.471
radiation (λ), Å
2θ range, deg
µ, mm-1
Mo KR (0.71073)
3.7 to 50.0
2.512
Mo KR (0.71073)
3.5 to 50.0
1.625
Mo KR (0.71073)
3.7 to 52.0
3.254
Mo KR (0.71073)
3.4 to 52.0
1.464
F(000)
1568
1524
1296
2576
no. of obsd reflns
no. of params refnd
goodness of fit
R1
6463
416
0.924
0.061
9945
759
1.051
0.065
5734
326
0.967
0.048
4171
364
1.205
0.068
wR2
0.138
0.179
0.107
0.162
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles (d eg)a
4
5
6
7
8
9
10
11
(Yb)
12
(Yb)
(Ln)
(Yb)
(Sm)
(Yb)
(Yb)
(Sm)
(Yb)
(Sm)
av Ln-C(ring)
av. Ln-C(cage)
av Ln-Cl
av Ln-N (sidearm)
av C(ring)-Si-C(cage)
av Cent-Ln-C(cage)
2.668(3)
2.520(3)
2.508(1)
2.617(3)
107.6(1)
105.2
2.757(3)
2.627(3)
2.793(1)
2.665(2)
107.0(1)
100.2
2.705(8)
2.547(7)
2.703(1)
2.619(6)
105.3(3)
103.2
2.617(9)
2.438(8)
2.645(2)
2.527(7)
104.9(4)
104.7
2.722(14)
2.591(14)
2.752(4)
2.648(11)
106.8(7)
100.3
2.609(11)
2.413(11)
2.732(8)
2.742(8)
2.510(9)
2.830(8)
2.643(9)
2.678(3)
2.787(8)
102.0(4)
2.457(10)
106.0(5)
106.9
2.585(8)
109.3(4)
103.9
111.4(4)
106.4
a
Cent: the centroid of the five-membered ring of the indenyl group.
Rea ction w ith Ln Cl3. Treatment of 3 with 1 equiv
of YbCl3 at room temperature gave an ionic complex,
[{η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)}YbCl2]-
[Li(THF)4] (4), in 78% yield. A THF/toluene solution of
4 was heated at reflux temperature for 2 h to produce,
after workup, a complex salt of [{η5:η1:σ-Me2Si(C9H5-
CH2CH2NMe2)(C2B10H10)}Yb(µ-Cl)1.5]2[Li(THF)4] (6) via
the elimination of 1 equiv of LiCl. Prolonged heating of
a toluene solution of 6 at reflux temperature led to
removal of another equivalent of LiCl, generating the
dimeric neutral species [{η5:η1:σ-Me2Si(C9H5CH2CH2-
NMe2)(C2B10H10)}Yb(µ-Cl)]2 (7) in 58% yield. The sa-
marium analogue of 6, [{η5:η1:σ-Me2Si(C9H5CH2CH2-
NMe2)(C2B10H10)}Sm(µ-Cl)1.5]2[Li(THF)4] (5), was directly
prepared from the reaction of 3 with 1 equiv of SmCl3
in THF at room temperature. It is noted that no Sm
analogue of 4 was isolated even though the reaction
conditions and workup procedures were the same,
probably owing to steric reasons. These transformations
are summarized in Scheme 2.

3784 Organometallics, Vol. 23, No. 16, 2004
Wang et al.
Sch em e 1
F igu r e 1. Molecular structure of the anion [{η5:η1:σ-Me2-
Si(C9H5CH2CH2NMe2)(C2B10H10)}YbCl2]- in 4. Selected
bond distances (Å) and angles (deg): Yb1-C1 ) 2.520(3),
Yb1-Cl1 ) 2.498(1), Yb1-Cl2 ) 2.518(1), Yb1-N1 )
2.617(3), av Yb1-C(ring) ) 2.668(3), Cent-Yb1-C1 )
105.2.
Sch em e 2
F igu r e 2. Molecular structure of the anion [{η5:η1:σ-Me2-
-
Si(C9H5CH2CH2NMe2)(C2B10H10)}Yb(µ-Cl)1.5
]
2
in 6. Se-
lected bond distances (Å) and angles (deg): Yb1-C1 )
2.565(7), Yb2-C21 ) 2.529(8), Yb1-Cl1 ) 2.678(2), Yb1-
Cl2 ) 2.726(2), Yb1-Cl3 ) 2.718(2), Yb1-N1 ) 2.600(6),
Yb2-Cl1 ) 2.703(2), Yb2-Cl2 ) 2.737(2), Yb2-Cl3 )
2.658(2), Yb2-N2 ) 2.637(6), av Yb1-C(ring) ) 2.704(8),
av Yb2-C(ring) ) 2.705(8), Cent1-Yb1-C1 ) 103.1,
Cent2-Yb2-C21 ) 103.2.
appended amine group in a four-legged piano stool
arrangement (Figure 1). This type of structures is very
rare in organolanthanide chemistry, whereas the chlo-
rine-bridged “ate” ones are very common.2
Single-crystal X-ray analyses reveal that 5 and 6 are
isostructural and isomorphous, consisting of well-
separated, alternating layers of the discrete tetrahedral
cations [Li(THF)4]+ and the complex anions [{η5:η1:σ-
Complexes 4-7 are paramagnetic species and do not
offer much useful NMR information. The ligand-to-
1
solvent ratios were measured by the H NMR spectra
of the hydrolysis products of the complexes. Their
structures were confirmed by single-crystal X-ray dif-
fraction studies.
Me2Si(C9H5CH2CH2NMe2)(C2B10H10)}Ln(µ-Cl)1.5]2
-. The
asymmetric unit of 5 contains one THF of solvation,
whereas that of 6 shows one toluene of solvation. In the
anion, each Ln atom in the dimeric unit is η5-bound to
one five-membered ring of the indenyl group and
σ-bound to one cage carbon atom, three doubly bridging
Cl atoms, and one nitrogen atom from the sidearm in a
distorted-octahedral coordination environment (Figure
2).
The molecular structure of 4 consists of well-sepa-
rated, alternating layers of the discrete tetrahedral
cations [Li(THF)4]+ and anions [{η5:η1:σ-Me2Si(C9H5-
CH2CH2NMe2)(C2B10H10)}YbCl2]-. In the anion, the Yb
atom is η5-bound to one five-membered ring of the
indenyl group and σ-bound to one cage carbon atom, two
terminal Cl atoms, and one nitrogen atom from the

Linked Carboranyl-Indenyl Ligand
Organometallics, Vol. 23, No. 16, 2004 3785
F igu r e 4. Molecular structure of [η5:η1:σ-Me2Si(C9H5CH2-
CH 2NMe2)(C2B10H 10)]Sm (µ-NH C6H 3-2,6-P r i2)(µ-Cl)Li-
(THF) (8). Selected bond distances (Å) and angles (deg):
Sm1-C1 ) 2.591(14), Sm1-N1 ) 2.380(12), Sm1-N2 )
2.648(11), Sm1-Cl1 ) 2.752(4), Cent-Sm1-C1 ) 100.3.
F igu r e 3. Molecular structure of [{η5:η1:σ-Me2Si(C9H5CH2-
CH2NMe2)(C2B10H10)}Yb(µ-Cl)]2 (7). Selected bond dis-
tances (Å) and angles (deg): Yb1-C1 ) 2.438(8), Yb1-N1
) 2.527(7), Yb1-Cl3 ) 2.675(2), Yb1-Cl3A ) 2.614(2), av
Yb1-C(ring) ) 2.617(9), Cent-Yb1-C1 ) 104.7, Yb1-
Cl3-Yb1A ) 104.54(8).
The solid-state structure of 7 is shown in Figure 3,
indicating that it is a centrosymmetric dimer. The
coordination environment of each Yb atom is similar to
that observed in 4.
The structural data of 4, 6, and 7 (Table 3) show the
following trends: (1) for Ln-C(ring, cage) and Ln-N
bond distances, 6 > 4 > 7; and (2) for Ln-Cl distances,
6 > 7 > 4. These results are understandable since the
Yb atom in 6 is eight-coordinate, whereas the seven-
coordinate Yb in 4 is bonded to two terminal Cl-, and
the seven-coordinate Yb in 7 is bonded to one bridging
Cl- and one bridging Cl atom, respectively.11 These mea-
sured values are close to those found in [{[η5:σ-Me2Si-
(C9H5CH2CH2OMe)(C2B10H10)]Ln(THF)(µ-Cl)3Ln[η5:η1:
σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]}2{Li(THF)}][Li-
(THF)4],3 [η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]-
Ln(THF)(µ-Cl)2Ln[η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2-
B10H10)],3 and [η5:σ-Me2Si(C9H6)(C2B10H10)]2Ln-,8 if the
differences in Shannon’s ionic radii are taken into
account.11
F igu r e 5. Molecular structure of [η5:η1:σ-Me2Si(C9H5CH2-
CH2NMe2)(C2B10H10)]Yb(NHC6H3-2,6-Pri2) (9). Selected bond
distances (Å) and angles (deg): Yb1-C1 ) 2.413(11), Yb1-
N1 ) 2.457(10), Yb1-N2 ) 2.140(9), av Yb1-C(ring) )
2.609(11), Cent-Yb1-C1 ) 106.9.
The above results show that 4 was converted to 6 and
finally to 7 upon heating by eliminating LiCl step by
step. Therefore, 4 is suggested to be a kinetic product
and 7 is a thermodynamic one. Very low solubility of
LiCl in hot toluene provides a driving force for these
transformations. Comparing the molecular structure of
7 with that of the ether-functionalized analogue, [η5:η1:
σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]Yb(THF)(µ-Cl)2Yb-
[η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)],3 steric ef-
fects imposed by the coordination of the Me2N moiety
to the Yb atom are very obvious, which reduce the coor-
dination number of the central metal ion by one unit.
Like most lanthanocene chlorides,2,3 the chloro groups
in the above complexes were able to be replaced by other
units via salt metathesis reactions. Treatment of 5 or 6
with 2 equiv of sodium amide gave the “ate” complex
[η5:η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)]Sm(µ-NHC6-
η1:σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)]Yb(NHC6H3-
2,6-Pri ) (9) in good yields, shown in Scheme 2. It is
2
noted that reactions of 6 with alkylating reagents such
as CH3Li, Me3SiCH2M (M ) Li, K), and Me3SiCH2MgCl
were complicated, and no pure products were isolated.
Unlike complex 9, the coordinated LiCl in 8 cannot be
removed by recrystallization from hot toluene, probably
because of the larger ionic radius of the Sm3+ ion.
Careful examination of the molecular structures of 9
and its ether-functionalized analogue, [η5:η1:σ-Me2Si-
(C9H5CH2CH2OMe)(C2B10H10)]Yb(NHC6H3-2,6-Pri )(µ-
2
Cl)Li(THF)3,3 may conclude that the coordination of
NMe2 forces the dissociation of LiCl from the central
metal ion during recrystallization. Again, steric factors
play a role in these transformations.
Single-crystal X-ray analyses confirm the molecular
structures of both 8 and 9, shown in Figures 4 and 5,
respectively. 8 exhibits a distorted-trigonal-bipyramidal
arrangement of ligands with the Cl atom and the
H3-2,6-Pri )(µ-Cl)Li(THF) (8) or the neutral species [η5:
2
(11) Shannon, R. D. Acta Crystallogr. 1976, A32, 751.

3786 Organometallics, Vol. 23, No. 16, 2004
Wang et al.
Sch em e 4
F igu r e 6. Molecular structure of the anion [{η5:η1:η6-Me2-
Si(C9H5CH2CH2NMe2)(C2B10H10)Sm}2(µ-Cl)]- in 10. Se-
lected bond distances (Å) and angles (deg): C2-C2′ )
1.509(10), Sm1-Cl1 ) 2.688(3), Sm1′-Cl1 ) 2.668(3),
Sm1-N1 ) 2.709(8), Sm1′-N1′ ) 2.665(8), av Sm1-
C(ring) ) 2.731(9), av Sm1-cage atom ) 2.815(10), av
Sm1′-C(ring) ) 2.732(8), av Sm1′-cage atom ) 2.804(10),
Sm1-Cl1-Sm1′ ) 120.1(1).
Sch em e 3
comparable to the corresponding values observed in [{η5:
η1:η6-Me2Si(C9H5CH2CH2OMe)(C2B10H10)Sm}2(µ-Cl)][Li-
(THF)4]3 and [η5:η6-Me2Si(C9H6)(C2B10H11)]Sm(THF)2.12
The average Sm-Cl(µ) distance of 2.678(3) Å is slightly
longer than the corresponding value of 2.645(4) Å in
[{η5:η1:η6-Me2Si(C9H5CH2CH2OMe)(C2B10H10)Sm}2(µ-
Cl)][Li(THF)4],3 but is much shorter than the 2.76(1) Å
in [{(η5-C5Me5)2SmCl}2(µ-Cl)]- and 2.88(2) Å in [(η5-C5-
Me5)2Sm(µ-Cl)]3,13 implying that steric repulsion plays
an important role.
centroid of the five-membered ring occupying the axial
positions. On the other hand, 9 shows a distorted-
tetrahedral arrangement of ligands. The bond distances
observed in 8 and 9 (Table 3) are comparable to the
corresponding values found in [η5:η1:σ-Me2Si(C9H5-
An equimolar reaction of less reactive YbI2 with 3 in
THF produced, after recrystallization from a toluene/
DME solution, the divalent ytterbium complex [η5:η1:
σ-Me2Si(C9H5CH2CH2NMe2)(C2B10H10)]Yb(DME) (11) in
66% yield. Treatment of 11 with 1 equiv of 3 gave the
ionic complex {[(µ-η5:η2):η1:σ-Me2Si(C9H5CH2CH2NMe2)-
(C2B10H10)]2Yb}{Li(THF)2}2 (12) in 71% yield. Complex
12 was also directly prepared from the reaction of YbI2
with 2 equiv of 3 in THF. These reactions are sum-
marized in Scheme 4.
CH2CH2OMe)(C2B10H10)]Ln(NHC6H3-2,6-Pri )(µ-Cl)Li-
2
(THF)3 and other organolanthanide complexes2 if the
3
differences in Shannon’s ionic radii are taken into
account.11
Rea ction w ith Ln I2. Treatment of SmI2 with 1 equiv
of 3 in THF at room temperature gave, after addition
of LiCl, the ionic complex [{η5:η1:η6-Me2Si(C9H5CH2CH2-
NMe2)(C2B10H10)Sm}2(µ-Cl)][Li(THF)4] (10) as dark red
crystals in 43% yield (Scheme 3). This complex was
originally isolated from an equimolar reaction of [Me2-
Si(C9H5CH2CH2NMe2)(C2B10H10)]Li2(OEt2)2‚LiCl with
SmI2 in THF.4
A single-crystal X-ray diffraction study confirms that
10 is a trivalent samarium complex, consisting of well-
separated, alternating layers of discrete tetrahedral
cations [Li(THF)4]+ and complex anions [{η5:η1:η6-Me2-
Si(C9H5CH2CH2NMe2)(C2B10H10)Sm}2(µ-Cl)]- and shows
one toluene of solvation. The coordination geometry of
the Sm atoms in 10 is similar to that observed in the
ether-functionalized analogue [{η:5η1:η6-Me2Si(C9H5CH2-
CH2OMe)(C2B10H10)Sm}2(µ-Cl)][Li(THF)4],3 shown in
Figure 6. The two nido-C2B10H10 units are connected to
each other through a C-C single bond at a distance of
1.509(10) Å, and the dihedral angle between two six-
membered C2B4 rings is 63.3°.
1
The H NMR spectra show the presence of the hybrid
ligand and DME in a molar ratio of 1:1 for 11 and
support the molar ratio of two THF molecules per hybrid
ligand in 12, respectively. The splitting patterns of the
11B NMR spectra are 2:3 in 11 and 1:2:2 in 12,
respectively. Their solid-state IR spectra display a
characteristic B-H absorption of a closo-carborane at
about 2555 cm-1
.
The molecular structure of 11 is shown in Figure 7.
The Yb atom is η5-bound to the five-membered ring of
the indenyl group, σ-bound to the carborane cage carbon
atom, and coordinated to one nitrogen atom from the
sidearm and two oxygen atoms from one DME molecule
in a four-legged piano stool arrangement with a formal
coordination number of 7. This is another example
showing the differences between [Me2Si(C9H5CH2CH2-
(12) Xie, Z.; Wang, S.; Yang, Q.; Mak, T. C. W. Organometallics 1999,
18, 2420.
(13) Evans, W. J .; Drummond, D. K.; Grate, J . W.; Zhang, H.;
Atwood, J . L. J . Am. Chem. Soc. 1987, 109, 3928.
The average Sm-C(ring) and Sm-cage atom dis-
tances of 2.732(8) and 2.809(8) Å in 10 are very

Linked Carboranyl-Indenyl Ligand
Organometallics, Vol. 23, No. 16, 2004 3787
F igu r e 7. Molecular structure of [η5:η1:σ-Me2Si(C9H5CH2-
CH2NMe2)(C2B10H10)]Yb(DME) (11). Selected bond dis-
tances (Å) and angles (deg): Yb1-C1 ) 2.510(9), Yb1-N1
) 2.585(8), Yb1-O1 ) 2.388(7), Yb1-O2 ) 2.506(6), av
Yb1-C(ring) ) 2.742(8), Cent-Yb1-C1 ) 103.9.
NMe2)(C2B10H10)]2- and [Me2Si(C9H5CH2CH2OMe)(C2B10-
H
The solid-state structure of 12 was confirmed by
F igu r e 8. Molecular structure of {[(µ-η5:η2):η1:σ-Me2Si-
(C9H5CH2CH2NMe2)(C2B10H10)]2Yb}{Li(THF)2}2 (12). Se-
lected bond distances (Å) and angles (deg): Yb1-C1 )
2.643(9), av Yb1-C(ring) ) 2.830(8), Li1-C12 ) 2.45(2),
Li1-C13 ) 2.400(9), Cent-Yb1-C1 ) 106.4, Cent-Yb1-
Cent ) 128.5.
10)]2- in coordination chemistry.
single-crystal X-ray analysis, shown in Figure 8. The
Yb atom is η5-bound to each of two five-membered rings
of the indenyl groups and σ-bound to each of two car-
borane cage carbon atoms in a distorted-tetrahedral geo-
metry, which is very similar to that of {[(µ-η5:η2):η1:σ-Me2-
Si(C9H5CH2CH2OMe)(C2B10H10)]2Yb}{Li(THF)2}2.3
The Yb-C(ring), Yb-C(cage), Yb-N, and Yb-O dis-
tances in both 11 and 12 (Table 3) are comparable to
the corresponding values observed in [η5:η1:σ-Me2Si-
(C9H5CH2CH2OMe)(C2B10H10)]Yb(DME)(THF),3 {[(µ-η5:
η2):η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]2Yb}{Li-
(THF)2}2,3 [η5:σ-Pri2NP(C9H6)(C2B10H10)]Yb(DME)2,14 [η5:
σ-Me2C(C9H6)(C2B10H10)]Yb(DME)2,15 and other ytterb-
ium(II) complexes16 if the differences in Shannon’s ionic
radii are taken into account.11
coupling products. On the other hand, steric effects
imposed by the coordination of NMe2 to the central
metal ion are greater than those resulting from the
coordination of OMe, usually leading to the decrease in
the coordination number of the central metal ions and
the isolation of kinetic products and monomeric neutral
species. Such a sidearm effect also results in different
structures of early and late lanthanide complexes.
Ack n ow led gm en t. The work described in this paper
was supported by a grant from the Research Grants
Council of the Hong Kong Special Administration
Region (Project No. CUHK4026/02P). Z.X. acknowledges
the Croucher Foundation for a Senior Research Fellow-
ship Award. S.W. thanks the Excellent Young Scholars
Foundation of Anhui Province and the Postdoctoral
Fellowship of the Chinese University of Hong Kong.
Con clu sion
The amine-functionalized carboranyl-indenyl hybrid
ligand shows features similar to the ether-functionalized
one. Both of them can prevent lanthanocene chlorides
from ligand redistribution reactions via coordinating to
the metal ion to meet steric requirements, and offer
divalent samarium complexes unusual reactivities,
resulting in the formation of unexpected reduction/
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data and data collection details, atomic coordinates, bond
distances and angles, anisotropic thermal parameters, and
hydrogen atom coordinates for complexes 4-12 as CIF files.
This material is available free of charge via the Internet at
http:/pubs.acs.org.
(14) Wang, H.; Wang, H.; Li, H.-W.; Xie, Z. Organometallics 2004,
23, 875.
(15) Wang, S.; Yang, Q.; Mak, T. C. W.; Xie, Z. Organometallics 2000,
19, 334.
(16) Sheng, E.; Wang, S.; Yang, G.; Zhou, S.; Cheng, L.; Zhang, K.;
Huang, Z. Organometallics 2003, 22, 684.
OM049778+